| 摘要 |
PURPOSE:To promote the integrated and shared use of a keyboard by allocating the data for selection of modes to an idle port of a controller having a scan type keyboard. CONSTITUTION:A microprocessor (control part) 11 for control of keyboard which controls the transfer of data between a key matrix circuit 12 and the main body of a device always transfers the data obtained through the key scan to said main body. The circuit 12 contains switches arrayed in a matrix and is scanned by the signal produced by a decoder 13 with the key address given from the control part 11. Here the 3-bit ports P0-P2 are allocated to the scan purpose among those 8-bit ports of the part 11. While a 1-bit port P7 is allocated to the mode setting purpose. Then the lock-out/roll-over mode is set by a switch 14. Thus the part 11 refers to the port P7 before scanning and then recognizes the relevant mode for scanning.
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